Sage-Tips

What can you tell about the ages of the ocean basins?

Scientists use the magnetic polarity of the sea floor to determine the age. Very little of the sea floor is older than 150 million years. This is because the oldest sea floor is subducted under other plates and replaces by new surfaces.

How old are the oldest rocks in the ocean basins?

All of the ocean basins were formed from volcanic rock that was released from fissures located at the mid-oceanic ridges. The oldest rocks found in these basins are approximately 200 million years old. This is a lot younger than the oldest continental rocks which have ages greater than 4 billion years.

How does the age of oceanic rock serve as evidence for seafloor spreading?

The age, density, and thickness of oceanic crust increases with distance from the mid-ocean ridge. The magnetism of mid-ocean ridges helped scientists first identify the process of seafloor spreading in the early 20th century. Oceanic crust slowly moves away from mid-ocean ridges and sites of seafloor spreading.

What is the most accurate method used by geologists to determine the age of igneous rocks on the ocean floor near the Mid Atlantic ridge?

Ocean floor rock is 200 million years older or less, as determined by radiometric dating and interpreting magnetic reversal patterns.

How did the ocean basins evolve?

Chapter 3 – The evolution of ocean basins Ocean basins form initially by the stretching and splitting (rifting) of continental crust and by the rise of mantle material and magma into the crack to form new oceanic lithosphere. Among the major ocean basins, the Atlantic has the simplest pattern of ocean-floor ages.

What age are the youngest rocks in the Atlantic Ocean?

They found that the youngest rocks on the seafloor were at the mid-ocean ridges. The rocks get older with distance from the ridge crest. The scientists were surprised to find that the oldest seafloor is less than 180 million years old. This may seem old, but the oldest continental crust is around 4 billion years old.

What happens to older oceanic crust as new rock is formed?

This process occurs when oceanic crust is pushed back into the mantle at subduction zones. As old oceanic crust is subducted and melted into magma, new oceanic crust in the form of igneous rock is formed at mid-ocean ridges and volcanic hotspots.

Do the ages of oceanic rocks get older as you move away from the ridge?

Scientists can determine the age of the seafloor by examining the changing magnetic field of our planet. While it cools down, it records the magnetic field during its formation. The two parts of the oceanic plate are pulled apart, and magnetic stripes become older as they move away from the mid-ocean ridge.

How will you explain the age of the rocks found in seafloor 200 million years ago being younger than the rocks present in the continental crust 3.96 billion years ago )?

Why is the seafloor so young? It is due to the process of subduction; oceanic crust tends to get colder and denser with age as it spreads off the mid-ocean ridges. It gets so dense, that it sinks in the upper mantle (subduction). This is like a giant recycling system for the oceanic lithosphere.

How did ocean basins evolve what are its feature?

Ocean Basin Types and Formation Active ocean basins undergo change mainly due to plate tectonics. Plate tectonics is the theory used to explain the dynamics of the earth’s surface resulting from the interaction of the overlying rigid plates with the underlying mantle.